Embodiments described herein relate to an uninterruptible power supply (UPS).
As the electronic technology continues to develop, the requirement for the quality of power supply systems also rises constantly. Since UPS can provide a load in time with continuous, stable and pure AC sine wave power when the load is disconnected abruptly so as to avoid accidents such as data loss and error, device damage or uncontrolled crash, operation cease, etc., it has been widely used in industries that employ electronic devices.
In general, as a backup power supply apparatus for electronic devices, the UPS, when the mains electricity is normally inputted, regulates the power and then supplies it to the load, and meanwhile, a built-in battery of the UPS machine is charged and energy is stored in the battery; whereas when the mains electricity is disrupted suddenly (accidental power cut), the UPS immediately converts the energy in the built-in battery into AC power for continued use by the load, enabling the load to maintain normal operation and protecting the load from both software and hardware damages.
However, people attach basically most importance to the quality of power supplied by the UPS to a load while care less about the status of the UPS when the load is unused or powered off. In that case, the UPS is usually left to remain powering on, which means that the UPS wastes its backup energy and enters a small-current (silk-current) discharging cycle. Generally, UPS has only several hundred discharging cycles, and more wasting means shorter life-cycle, which is not good for users.